1. Field of the Invention
The present invention relates to an organic electro-luminescence display (OLED), and more particularly to an OLED with different protective films formed over different light organic electro-luminescence devices.
2. Description of the Related Art
Due to the advance of technology, technology with respect to semiconductor devices and displays also dramatically progresses. Among displays, organic electro-luminescence displays (OLEDs) have no restriction of view angle; low manufacturing costs; high response speed, more than one hundred folds of response speed of liquid crystal displays; low-power consumption; direct current driving function applicable to portable apparatuses; wide operational temperature range; light weight; small dimension varying with hardware; and slimness. Thus, OLEDs have met the requirements of multi-media displays. OLEDs are also very promising and may become the main trend of next-generation panel displays.
In the luminescent mechanism of an OLED, electrons and holes are met within the organic material layer to emit photons. General organic materials are vulnerable to moisture and oxidation. As a result, the material properties may be changed, which affects luminescence or even makes luminescent devices failed. Therefore, during manufacturing OLEDs, how to prevent the organic material layer being moistened and oxidized becomes an essential topic.
FIG. 1A is a cross sectional view of a portion of a conventional OLED. Referring to FIG. 1A, the conventional OLED 100 comprises a substrate 110, a plurality of organic electro-luminescence devices 120 and a protective film 130. Wherein, the organic electro-luminescence devices 120 are disposed over the substrate 110. The organic electro-luminescence devices 120 comprise red, green and blue light organic electro-luminescence devices 120a, 120b and 120c, respectively. The protective film 130 covers the organic electro-luminescence devices 120 to prevent outside moisture and oxygen from penetrating into the organic electro-luminescence devices 120 so that the material and luminescent property of the organic electro-luminescence devices 120 can be maintained. Wherein, the material of the protective film 130 usually is silicon nitride.
Another conventional OLED comprises a protective cap to prevent the outside moisture and oxygen from penetrating into the organic electro-luminescence devices. As shown in FIG. 1B, the conventional OLED 101 comprises the substrate 110, a plurality of organic electro-luminescence devices 120 and a protective cap 140. Wherein, the material of the protective cap 140 usually is glass or metal.
In these conventional OLEDs 100 and 101, red light, green light and blue light emitted from the red, green and blue light organic electro-luminescence devices 120a, 120b and 120c, respectively, have different light penetration rates to the protective film 130 or the protective cap 140 due to the different wavelengths of the red light, green light and blue light. After penetrating through the protective film 130 or the protective cap 140, red light, green light and blue light cannot achieve its optimized light intensity respectively.